Introduction

The Meldin 7000 Series Design Guide by Saint-Gobain Performance Plastics provides detailed information on the Meldin 7000 series, a family of polyimide, thermosetting materials known for their high dimensional stability and minimal degradation at elevated temperatures. These materials are ideal for high-temperature applications due to their wear resistance, chemical resistance, and electrical properties. The guide emphasizes the company's control over the production process, ensuring high-quality standards.

Mechanical Properties vs. Temperature

The mechanical properties of Meldin 7000 series materials, such as tensile and flexural strength, decrease linearly with increasing temperature. These materials can operate continuously at 315°C and intermittently at 482°C. The guide includes graphs showing the relationship between temperature and mechanical properties, aiding engineers in predicting performance under various conditions.

Flexural Strength vs. Temperature

Meldin 7000 materials exhibit a gradual decline in flexural strength with temperature, unlike many plastics that show a sharp decrease at their glass transition temperature. The presence of fillers affects the initial property values and the rate of decline.

Stress-Strain Information

The stress-strain behavior of Meldin 7000 materials shows no transition from elastic to plastic deformation, indicating brittleness in filled materials compared to unfilled ones. The guide provides stress-strain graphs for both ambient and high-temperature conditions.

Direct Formed Stress-Strain

Stress-strain properties measured perpendicular to the forming direction are slightly lower, reflecting anisotropy in material properties. The guide includes graphs for these measurements at different temperatures.

Stress-Strain Under Compression

Meldin 7000 materials can withstand high strain conditions without failure, making them suitable for seals and bearings. The guide provides compression stress-strain graphs at various temperatures.

Linear Thermal Expansion

The coefficient of linear thermal expansion is provided for the temperature range of 23°C to 300°C, highlighting the material's stability under thermal stress.

Conclusion

The guide concludes with a note on the importance of testing Meldin 7000 materials in actual applications to ensure suitability, as Saint-Gobain does not assume liability for performance outcomes. The document serves as a valuable resource for design engineers in selecting and specifying Meldin 7000 series materials.

Overview

The document provides detailed technical specifications, properties, and guidelines for the Meldin 7000 series polyimide materials, focusing on their mechanical, thermal, and electrical properties, as well as their resistance to various chemicals and flammability ratings. It also includes machining guidelines and application recommendations.

Specifications

The document outlines the mechanical properties of different Meldin grades (7001, 7021, 7022, 7211, 7003) at room temperature and elevated temperatures (500°F/260°C). Key properties include tensile strength, elongation, flexural strength, compressive stress, and modulus. The coefficient of thermal expansion and thermal conductivity are also specified.

Procedures

The document describes the testing methods used to determine the properties of Meldin materials, including ASTM standards for tensile strength (D638), flexural strength (D790), compressive stress (D695), and thermal expansion (E831). It also details the creep testing procedures and results for Meldin 7001, 7021, and 7022 under various loads and temperatures.

Norms and Standards

Meldin materials meet several industry standards, including ASTM D 6456-99, AMS SAE 3644G, and MIL-R-46198, ensuring their suitability for aerospace and other high-performance applications.

Recommendations

The document provides machining guidelines for Meldin 7000 materials, recommending specific tooling, feed rates, and holding methods to achieve optimal results. It emphasizes the importance of using appropriate tools and techniques to maintain the material's dimensional stability and surface finish.

Key Data from Figures and Tables

The document includes stress-strain curves for Meldin materials at different temperatures, showing their performance under compression. It also presents data on linear thermal expansion and chemical resistance, highlighting the materials' stability and resistance to various chemicals and conditions.

Applications

Meldin materials are recommended for use in high-temperature environments, electrical insulation, and applications requiring wear resistance and dimensional stability, such as bearings, thrust washers, and sealing rings.

Specifications and Procedures

The document outlines the "go/no-go" method for measuring tolerances using a micrometer. The micrometer is set at the high end of the tolerance to check if the piece passes through without drag, indicating acceptability. Similarly, at the low end, any resistance indicates the piece is above the low tolerance and acceptable. Pins should not be forced through a bore; they should fall through by their own weight.

Basic Shapes and Materials

Meldin® 7000 series materials are available in various basic shapes such as blocks, disks, rods, and tubes, offering design flexibility and optimal material utilization. The document provides detailed dimensions for these shapes, including blocks, disks, tubes, and molded rods, both isostatic and compression molded.

Contact Information

The document lists contact details for Saint-Gobain Performance Plastics locations worldwide, including the USA, Mexico, Brazil, Germany, Spain, Belgium, Poland, China, Taiwan, South Korea, Japan, India, Italy, the UK, and Thailand.

Warranty and Disclaimer

Saint-Gobain Performance Plastics offers a limited warranty for six months from the date of sale, covering manufacturing defects. The company disclaims all other warranties, including implied warranties of merchantability and fitness for a particular purpose. Users are advised to perform their own tests to determine product suitability.

Additional Notes

The document emphasizes that Saint-Gobain does not assume responsibility for advice or the performance of installations or use of the products. Meldin® is a registered trademark of Saint-Gobain Performance Plastics Corporation.